I get customers asking all the time about having to mark Form 1 guns so I thought I would post what I tell them.
Legally all Form1 guns should be marked with the makers name as it is written on the form 1 and the city and state. It can be marked on the receiver or the barrel but it may not covered up buy the stock, hand guards etc. The marking must be LEGIBLE, 1/16" tall and .003" deep in the base material not in the painted finish.
Tech branch has told me in a phone conversation they are more interested in the person having a completed Form1 then having the gun marked but the law says the gun needs to be marked. Tech branch may not be too concerned but I would not want to be standing in front of a hard nosed ATF field agent and not have my Form 1 gun marked just to save a couple of bucks.
Be careful who you have engrave your gun.
1) Unless a trophy shop has an FFL you can not leave your receiver with them to engrave.
2) Most trophy shops don’t have the proper equipment to engrave steel or aluminum to the proper legal depth.
3) Make sure whoever does your engraving knows the rules about what is acceptable and what is not.